Latch needle



Jan. ll, 1955 Q NOE 2,699,053

LATCH NEEDLE Filed Aug. 15, 1952 United States Patent Oce 2,699,053 Patented Jan. 11, 1955 LATCH NEEDLE Harold C. Noe, Upper Montclair, N. J., assignor to Kidde Manufacturing Co., Inc., Bloomfield, N. J., a corporation of Delaware Application August 1S, 1952, Serial No. 304,469

6 Claims. (Cl. 66-121) The present invention relates to knitting machine needles, and, more particularly, to an improved latch needle.

Latch needles for knitting machines generally comprise a shank having a substantially straight back edge, a hook at the free end of the shank having a point, a latch member having a substantially straight front edge and means for pivotally mounting the latch member on the shank so that the free end of the latch is adapted to engage the point and close the latch.

Heretofore, it has been customary to construct latch needles so that, when the latch is closed, the front edge of the latch member extends away from the back edge of the shank at a substantial angle, for example, as shown in United States Patent No. 84,472, dated Dec. 1, 1868, whereby the maximum dimension between the front and back surfaces of the hook appreciably exceeds the maximum dimension between the front and back edges of the shank at about the pivot of the latch member. Thus, in casting off a stitch formed about the shank, the loop of the stitch is enlarged as it is passed over the outwardly extending front edge of the latch member and the point of the hook against which the latch member rests when the latch is closed. Such unnecessary enlargement of the loop depreciates the appearance of the knitted fabric.

Accordingly, an object of the present invention is to overcome the foregoing difficulty by providing an irnproved latch needle which does not cause enlargement of loops in casting off stitches.

Another object is to provide such needles without increase in cost thereof.

A further object is to provide such needles without impairing the strength thereof.

A still further object is to provide such needles which are simple, practical and economical in construction and can be substituted for existing needles on a machine without modifying the construction or operation of the machine.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

ln accordance with the invention, it has been found that the foregoing objects can be accomplished by providing a latch needle for knitting machines which is so constructed and arranged whereby, when the latch is closed, the front edge of the latch member and the back edge of the shank are parallel to each other to prevent enlargement of loops while stitches are cast olf the needle.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification., wherein:

Fig. 1 is an enlarged side elevational view of a portion of a latch needle embodying the present invention.

Fig. 2 is a sectional view taken along the line 2-2 on Fig. '1.

Referring to the drawing in detail, there is shown a portion of a latch needle for knitting machines generally comprising a shank 10, a hook 11 at the upper end of the shank, and a latch member 12 pivotally mounted on the shank in the manner described hereinafter.

The shank is generally oval in cross-section and has liat sides 14 and 15, as shown in Fig. 2. The shank has a back edge 16 which is substantially straight and vertical, as viewed, and which extends to the point where thehook commences, and has a lower front edge portion 17 parallel to the back edge 16. The upper zone of the front edge of the shank is provided with an upwardly and outwardly tapering or diverging, substantially straight portion 18, and an upwardly and inwardly tapering or converging, substantially straight portion 19 adjacently above the portion 18 and meeting the same at the juncture point 20.

Preferably, the portions 18 and 19 taper at a very small angle, for example, less than about 6 to the vertical, whereby point 20 extends forwardly of the edge portion 17 only a small distance, for example, on the order of less than about one hundredth of an inch and does not cause enlargement of the loops of the stitches as they are being cast of the needle.

The front edge portions 18 and 19 of the shank are formed with a vertical slot or recess 21 intermediate the sides 14 and 15 (Fig. 2) which recess is of sufficient depth for receiving portions of the latch member 12 as described hereinafter. This recess may be in the form of a slot at the upper end between the hook and the latch pivot as is customary, or may have a rear surface 22 at the upper end which is inclined upwardly and outwardly, as viewed, at an angle not exceeding about 5 to the vertical. This recess further has a rear surface 24 at the lower end which is inclined downwardly and outwardly, as viewed, at an angle not exceeding about 5 to the vertical.

The hook 11 extends from the upper end of the shank and tapers as it terminates in a downwardly extending, slightly inwardly facing point 25 of generally circular cross-section.

The latch member 12 is a generally triangular element of a thickness to fit freely into the slot or recess 21 of the shank. This element has a substantially straight front edge 26 and a substantially straight back edge 2'7 inclined or tapered convergingly towards the front edge to provide a point 29 at the free end which is formed with a recess 3l) for receiving a portion of the point 25 of the hook. The other or wider end of this element is pivotally mounted by means of a pin 31 extending therethrough and through the shank. The pin 31, as viewed, is in horizontal alignment with the point 20 and is closer to the front edge than to the back edge of the shank.

The angle at which the back edge 27 of the latch member is disposed preferably does not exceed about 5. In practice, this angle is equal to the angle of taper of the recess surfaces 22 and 24, whereby, when the latch is closed as shown in full lines in Fig. l, the front edge 26 of the latch member is in parallel relation to the back edge 16 of the shank so that there is no zone of increasing cross-section between the juncture point 20 and the latch member point 29 which might cause enlargement of the loops as they are cast off the needle. Also, by reason of the aforedescribed construction, when the latch is down as shown in broken lines in Fig. l, the surface 24 and the edge 26 cooperate to position the back edge 27 of the latch member in parallelism with the back edge 16 of the shank so that the loops formed on the needle are of substantially the same peripheral dimension as is required for them to pass over the point 20 without enlargement when they are cast off.

From the foregoing description, it will be seen that the present invention provides an improved latch needle for knitting machines which is simple, practical, economical, and durable in construction but yet is streamlined to maintain the space occupied by the needle and its weight at a minimum. By reason of parallel edges of the front and back of the needle engaged by the yarn while the latch is either up (closed) or down (open), any tendency to unnecessarily enlarge the loops of the stitches is eliminated. This feature makes the needle particularly adapted for use in connection with high speed knitting machines where any tendency to enlarge loops while the knitting elements are moving rapidly may irnpair the quality of the knitted fabric.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. A latch needle for knitting machines comprising a shank having a front edge and a substantially straight back edge, a hook at one end of said shank having a point, a latch member having a substantially straight front edge, and means for pivotally mounting said latch member on said shank, said means being closer to said front edge of said shank than to said back edge of said shank along a line substantially perpendicular to said back edge of said shank, whereby, when the free end of said latch member engages said point, said front edge of said latch member and said back edge of said shank are parallel to each other.

2. A needle according to claim 1, wherein the maximum dimension between the front and back surfaces of said hook does not exceed the maximum dimension between the front and back edges of said shank at about the oivot of said latch member.

3. A latch needle for knitting machines comprising a ihank having a substantially straight back edge and havlng a front edge provided with a downwardly and outwardly tapering portion, a hook at the upper end of said shank having a point, a latch member having substantially straight converging back and front edges providing a point at one end thereof, and means pivotally mounting the end of said latch member opposite its point adjacent the lower end of said tapering portion of said shank, said means being constructed and arranged whereby when the point of said latch member faces upwardly and engages the point of said hook, said front edge of said latch member and said back edge of said shank are parallel to each other, and whereby, when the point of said latch member faces downwardly in a diametrically opposite direction, said back edge of said latch member and said back edge of said shank are parallel to each other.

4. A needle according to claim 3, wherein the distance between the front edge of said shank at said latch mounting means and the back edge of said shank is not exceeded by the maximum dimension between the front and back surfaces of said hook.

5. A needle according to claim 4, wherein the center of rotation of said pivotally mounting means is closer to the front edge of said shank than to the back edge of said shank.

6. A needle according to claim 4, wherein said shank includes a recess in the front edge thereof for receiving portions of said latch member to facilitate said latch being swung through an arc substantially equal to half a circle.

References Cited in the le of this patent UNITED STATES PATENTS 600,692 Huke et al. Mar. 15, 1898 1,168,039 Swinglehurst Jan. 11, 1916 OTHER REFERENCES Principles of Knitting, by Max C. Miller, published by McGraw-Hill Book Co., Inc., New York, 1931 edition, pages 62, 63. (Copy in Div. 21.) 

